ENERGY PARTITIONING DURING FISH DEVELOPMENT - ADDITIVE OR COMPENSATORY ALLOCATION OF ENERGY TO SUPPORT GROWTH

1. The goal of this study was to estimate the impact of the metabolic cost of growth (COG) on the energy budget of chinook salmon (Oncorhynchus tshawytscha) during embryonic and larval development. 2. In attempting to estimate COG, it was assumed that, as with juvenile and adult fish, energy is allocated in an additive fashion with respect to routine metabolism and mass-specific COG remains constant during early life. According to this model, there should be a direct relationship between metabolic intensity and specific growth rate. 3. In chinook salmon, however, there was no significant relationship between the two variables during embryonic development, during larval development, or during the combined embryonic-larval period at any of the four test temperatures (5.0, 7.5, 10.0 and 12.5-degrees-C). 4. The lack of correlation between metabolic intensity and specific growth rate suggests that the assumptions underpinning the additive model of energy partitioning may not hold during early life. An alternative model in which (a) energy is allocated in a compensatory manner and/or (b) mass-specific COG varies is presented.